An extremely wide, teethy smile. Often childish, and pretty much obnoxious and rude.

"That retard kept gloating everytime he laid eyes on me. I shoulda told him 'you're about two seconds away from wearing that smile around your ass'. But no, I'm a nice guy. Being a nice guy is actually a VERY difficult life, perhaps much harder than being a mean guy. Although it pays off, you have to be VERY patient too."
-me